362 



THE MICROSCOPE. 



Many of the smaller kinds of seeds will reward the 

 microscopist ; use only a low power ; that of Caryo- 

 phyllum (clove-pink), is regularly covered with curiously- 

 jagged divisions; every one of which has a small bright, 

 black hemispherical knob in its middle, represented in 

 fig. 160, A. 



The seeds of the carrot are remarkably formed, 

 having some resemblance to a star-iish, with its long 

 radiating processes. The seeds of umbelliferous plants 

 have peculiar receptacles for essential oil, in their coats, 

 termed vittce; various points of interest may be noted 

 as occurring in the testae, envelopes of seeds, such as 

 the fibre-cells of Cobcea, and the stellate cells of the 

 Star-anise. 



All plants are provided with hairs ; and a few, like 

 insects, with hairs of a defensive character. Those in 

 the Urtica dioica, commonly called the Stinging-nettle, are 

 elongated hairs, developed from the cuticle, usually of a 

 conical figure, and containing an irritating fluid ; in some 

 of them a circulation is visible : when examined under the 

 microscope, with a power of 100 diameters, they present 

 the appearance seen at fig. 188, No. 2. At No. 3, same 

 figure, are represented a few interesting ciliated spores 

 from Confervce. 



The circulation of the fluid-contents of vegetable cells 

 may be examined at the same time with the Chlorophyll 

 globules, by selecting for the purpose the transparent 

 water-plants Chara, Nitella, Anacharis, and Vallisneria, 

 or the hairs of Groundsel and Tradescantia. The circula- 

 tion of the sap in plants growing in water is termed by 

 botanists Gyclosis. 



Fossil plants. We detect in some of the primordial 

 fossils a noticeable likeness to families familiar to the 

 modern algseologist. The cord-like plant, Chorda filium, 

 known as ' dead men's ropes,' from its proving fatal at 

 times to the too adventurous swimmer who gets entangled 

 in its thick wreaths, had a Lower Silurian representative, 

 known to the palaeontologist as the Palceochorda, or 

 ancient chorda, which existed, apparently, in two species, 

 a larger and a smaller. The still better known Chondrus 

 crispus, the Irish moss, or Carrageen moss, has, likewise, 



